[DetectorHistogrammer] bug fix: Merged hit_map_global correctly.
A histogram was not merged correctly (or rather, hit_map_global was never merged, and hit_map_local duplicated instead). Also fixed the title of the histogram in question.
A histogram was not merged correctly (or rather, hit_map_global was never merged, and hit_map_local duplicated instead). Also fixed the title of the histogram in question.